make tests return nonzero if failing

http://codereview.appspot.com/4545042/



git-svn-id: http://skia.googlecode.com/svn/trunk@1323 2bbb7eff-a529-9590-31e7-b0007b416f81

tests/skia_test.cpp

@@ -123,5 +123,5 @@ int main (int argc, char * const argv[]) {
         SkDebugf("Finished %d tests, %d failures.\n", count,
                  count - successCount);
     }
-    return 0;
+    return (count == successCount) ? 0 : 1;
 }